Estimates of heat flux from direct measurements of vertical velocity-temperature
fluctuation correlations have been obtained from vertical profiles
through turbulent patches in the main thermocline. These have been compared
to more indirect flux estimates derived from dissipation rates of turbulent kinetic
energy and temperature variance. Because record lengths are limited by the
thickness of observed turbulent patches, uncertainties are larger than would be
expected from relatively longer horizontal records. The best estimate of dissipation
flux coefficient from these data is about 0.15-0.2, but it is characterized by a large
range of sample values. This implies mixing efficiencies (flux Richardson numbers)
are about 0.13-0.17. This is within the range of laboratory estimates but is different
from measurements in turbulent tidal fronts
